Dr. Bailey-Wilson joined a collaborative study of Attention Deficit Hyperactivity Disorder in this fiscal year, collaborating with Drs. Max Muenke and Kate Berg of NHGRI. Dr. Bailey-Wilson's role is to help with study design and to serve as statistical geneticist on the project. We have performed power studies of many large pedigrees from Columbia, showing that there will be adequate power in a future linkage study to detect genes of moderate to large effect, even in the presence of heterogeneity. Dr. Bailey-Wilson also advises the other collaborators about the types of pedigree structures that are particularly informative for linkage studies. This study is ongoing.